Centrifuges



United States Patent 3,282,433 CENTRIFUGES Dieter Pohl and Joachim Pohl, both of Salinenstr. 28, Bad Salzdethfurth, Germany Filed July 10, 1963, Ser. No. 294,012 Claims priority, application Germany, July 11, 1962,

4 Claims. 61. 210-369) Our present invention relates to centrifuges for the separation of solid materials from liquid in a fluent heterogeneous mixture thereof and, more particularly, to improved sugar centrifuges.

In general, sugar centrifuges have, heretofore, been of one of two principal types. It thus was known to provide a sugar centrifuge for the separation of sugar crystals from the mother liquor which comprised a perforate frustoconical centrifuge drum journaled within a housing for rotation about a substantially vertical axis and converging upwardly therewithin, means being provided adjacent an upper end of this drum for introducing a descending stream of the heterogeneous mixture into the interior of the latter for distribution onto the interior walls of the drum or basket. In conventional devices of this type, substantial disadvantages deriving from the tendency of the fluent mixture introduced at the inlet means to ride up along the drum and along these inlet means into its discharge aperture were experienced. The result is a tendency for the mixture fed into the drum to progressively block the outlet passage and prevent the substantially continuous influx of the material to be' separated. Earlier devices also made use of formations along the interior wall of the drum which tended to restrict free flow of the solids (i.e. the sugar crystals) downwardly along this perforated wall. Such formations were frequently required for the conventional inlet means described above. To obviate these disadvantages, it has been proposed, in another type of apparatus, to mount the centrifuge drum or basket so that it diverges upwardly and the fluid mixture is displaced vertically upwardly therealong. For the most part, centrifuges of this type have the additional disadvantage that substantially higher driving forces are required since even the solid components must be displaced counter to the gravitational force normally acting upon them. In centrifuges of the latter type, considerable attention must be paid to the construction of the drive means, the bearings supporting the centrifuge drum, and the output power and speed of the driving motor.

It is the principal object of the present invention, therefore, to provide a centrifuge for the separation of solids from liquids in a fluent heterogeneous mixture wherein the foregoing disadvantages can be eliminated.

Another object of this invention is to provide an improved inlet means for a centrifuge of this character where there is no tendency for the fluent mixture to block the discharge port of the inlet means. 1

Still another object of this invention is to provide an inlet means capable of efficiently distributing the fluent mixture along the interior of a frustoconical drum.

Yet a further object of this invention is to provide a sugar centrifuge capable of economically separating sugar crystals from the mother liquor with a minimum of driving energy.

These objects and others which will become apparent hereinafter are attained, in accordance with our present invention, by providing, in a centrifuge for the separation of solids from liquids in a fluent heterogeneous mixture, a downwardly diverging perforate centrifuge drum which is rotatable within a housing about a generally vertical axis and is provided with central inlet means for feeding the mixture onto the interior wall of the drum, the inlet means including at least one but preferably a plurality of spiroiice dally extending deflecting members coaxial with the drum and rotatable therewith while being disposed adjacent the discharge port or outlet of the inlet means for limiting upward movement of the mixture discharged at this out let. Advantageously, these deflecting members are connected with a tubular body coaxially mounted with respect to the drum and rotatable therewith, this tubular body having an inlet passage for the mixture terminating at this outlet within the interior of the drum. As the spi roidal deflecting members sweep in a closed path around the central outlet, they serve to deflect any portions of the mixture emanating therefrom, and not directly cast outwardly, to prevent their axial migration and thus act as an intercepting element adapted to direct these migrating portions of the mixture centrifugally outwardly onto the interior wall of the centrifuge drum. In contradistinction, axially extending members adjacent the outlet would tend to promote the axial migration of the fluent mixture into a position in which the outlet port is blocked.

According to another feature of the present invention, the inlet means also includes a bafiie body axially spaced from the tubular body and formed with a wall extending transversely to the axis thereof forwardly of the outlet port in the direction of influx of the mixture. This wall serves as a supplemental member for the centrifugal distribution of the fluid mixture onto the interior of the perforate centrifuge drum. Advantageously, the or each of the spiroidally extending deflecting members interconnects the bafile body and the aforementioned tubular body while spanning the. gap therebetween. Preferably, the tubular and baflle bodies are integrally formed with the spiroidal deflecting members, which are angularly equispaced therearound, and are removably disposed within the drum. For this purpose, the drum can be provided with a central hub at another'end thereof, the hub being formed with an upwardly tapering frustoconical bore adapted to receive the tubular body which is likewise provided with a slightly tapering frustoconical external configuration. Additionally, the drum can be equipped with means for axially fixing the tubular body within its frustoconical bore. The baffie body may have a downwandly diverging frustoconical configuration designed to insure the outward distribution of the fluent mixture even when the drum is rotating relatively slowly so as to direct this mixture into an annular receptacle surrounding the axis of rotation of the dmm and away from the central support 'sh'aft.

Still another feature of the present invention resides in the use of the inlet means :as a connecting member via which the centrifuge is rotated. Thus one of the bodies can be deta-chably-connected with the drive shaft of a motor or the like. When the baffle body is to be provided with the drive mean-s, it may be removably mounted, via a conical bore and shaft extension upon this shaft and serve to carry the centrifuge drumor basket via the splir-oidally extending deflecting members. In this case, these members also serve as a resilient mount-ing for the drum. Alternatively, the drive shaft may be coupled with the. tubular body provided with the inlet passage.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is an axial cross-sectional view through a centrifuge embodying the present invention;

FIG. 2 is an axial cross-sectional view illustrating the inlet means thereof in greater detail;

FIG. 3 is a view similar to FIG. 1 of a centrifuge according to a modification of the present invention;

FIG. 4 is an axial cross-sectional view through a por t-ion of the inlet means of the centrifuge of FIG. 3;

FIG. 5 is an elevational view of an inlet means, according to the present invention, provided with a multiplicity of deflecting members; and

FIG..6 is a cross-sectional view taken along the line VIVI of FIG. 5.

In FIGS. 1 and 2 we show a downwardly diverging frustoconical perforate centrifuge drum 1 which is provided at its upper end with a central hub 2 formed with an upwardly converging slightly tapering axially bore adapted to receive the upwardly tapering tubular body 3 of an inlet member 4 serving simultaneously as a connecting means joining the centrifuge drum or basket 1 with the drive shaft 6. The lower portion of inlet means 4 is formed as a baffle body- 5 having a frustoconical bore 13 adapted to be removably seated upon the upwardly tapering end of shaft 6. The centrifuge drum 1 is surrounded by a first housing portion 7 in which a mother liquor or a liquid component of the heterogeneous mixture is collected in the usual manner while the lower end 8 of drum 1 terminates at an annular collecting vessel 9, constituting the remainder of the housing means, in which the solid component (e.g. sugar crystals) of the heterogeneous mixture is deposited by gravity. As can best be seen in FIG. 2, tubular body 3 is connected with baflle body 5 by a spiroidally extending deflecting member 10, body 3 having a central passage 11 for the influx of the heterogeneous mixture. This passage 11 terminates in a c-onically widening outlet 11 through which the mixture is discharged. Spaced from outlet 11' and extending transversely to the axis of tubular body 3 is a wall 12 formed on the deflecting body 5, the latter being integral with the connecting element and tubular body 3. A look nut 14, threadedly enga-geable with tubular body 3, is provided in hub 2 to secure inlet means 4 in place.

A conduit 15 extends axially through passage 11 into the interior of drum 2 in order to discharge the heterogeneous mixture therein. The deflecting body 5 is provided with a frustoconical apron 16 of downwardly diverging configuration which serves to divert the stream from tube 15 outwardly into the collecting vessel 9 when the speed of drum 1 is low or when the latter is stationary. The deflecting member 10 prevents, upon rotation of drum 1 at high speeds, any of the influx mixture from blocking the inlet aperture. It has been found that the spiroidal members effectively catch any axially migrating portions of the mixture and cast it centrifugally outwardly onto the interior wall of perforate drum 1. Member 10 also acts'as a resilient support for the centrifuge drum 1 as previously noted. The pipes P are conventional and displace washing liquid onto the sugar crystals.

In FIGS. 3 and 4, we show a variant wherein the inlet means 21 is provided with a flange 21' to which the drive shaft 29 may be removably connected, an inlet conduit 28 passing through a 'lined passage in this drive shaft and the tubular body 22 of inlet means 21. In this embodiment, the upper part of the housing means 19 serves to collect extracted mother liquor which is removed at 19' while another collecting vessel 18 serves as a depository for the solid particles. In this case, the drum 17 is provided with a hub 20 mounted upon tubular body 22 and driven thereby. An annular groove 23' in tubular body 22 is engaged by a ring 20 on hub 20 to prevent axial shifting of drum 17 upon the inlet means. The hub is provided with an upwardly converging bore seated upon the upwardly tapering lower portion of tubular body 22 which has a passage 27 through which the inlet conduit 28 passes. A spiroidally extending member 24 connects tubular body 22 with its tapering portion 23 to the baffle body which, as previously described, is formed with a downwardly diverging frustoconical apron 26.

In the embodiment of FIGS. 5 and 6, the central body 30, which is formed with a wall transverse to the direction of influx of the heterogeneous mixture and spaced from the outlet of a passage 36 formed in the tubular body of the inlet means, is connected with the latter via a plurality of angularly equispaced spiroidal deflecting 4 members 31-34. Again the tubular body 35 is integral with the connecting elements 3134 and with the baffle body 30.

In all of these embodiments the drum 1, 17 etc. is set into rotation so that the inlet means rotates in the sense indicated, for example, by arrow 38 in FIG. 6. The heterogeneous mixture discharged via the central passages 11, 27, 36 of the inlet mean is cast centrifugally outwardly as indicated by the radial arrows in FIG. 6 onto the inner wall of the centrifuge drum. The mother liquor is forced by centrifugal action through the perforations in this drum and is collected via the surrounding housing while the solid material (e.g. the sugar crystals) travels downwardly along the d-rum and is collected in vessels 9', 18 etc. The deflecting members 10, 24, 31, 34 intercept any material in the gap in the outlet of tubular member 3, 22, 35 and facilitate its outward movement against the walls of the centrifuge drum. The material collected upon the transverse walls of baflle bodies 5, 25 and 30 is likewise cast centrifugally outwardly while the spiroidal deflecting elements prevent any upward migration. In tests employing centrifuges of the type illustrated in FIGS. 1-6, they have been found to be a marked improvement over the conventional devices and to be free from clogging or blocking of the outlet apertures of the inlet means in con tradistinction to earlier devices in which continuous operation of the centrifuge was prevented by such blocking.

The invention described and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the appended claims.

We claim:

1. In a centrifuge for the separation of solids from liquid in a fluent heterogeneous mixture thereof, in combination, housing means forming an enclosure; a downwardly diverging perforate centrifuge drum rotatable within said housing about a generally vertical axis; and inlet means for feeding said mixture onto the interior of said drum, said inlet means including a tubular body coaxially mounted with respect to said drum and rotatable therewith at an upper end thereof, said body being formed with a passage for said mixture terminating at an outlet within the interior of said drum, a baflle body axially spaced from said tubular body and formed with a wall extending transversely to the axis thereof forwardly of said outlet in the direction of flow of said mixture, and at least one rodshaped elongated deflecting member extending downwardly from said tubular body to said baffle body in at least one axially diverging spiral segment with adjacent spiral passageways transverse to said axis, the space bounded by said deflecting member between said tubular body and said bafllc body being unobstructed, the bodies and said deflecting member being jointly rotatable with said drum for limiting upward movement of the mixture discharged at said outlet.

2. In a centrifuge for the separation of solids from liquid in a fluent heterogeneous mixture thereof, in combination, housing means forming an enclosure; a downwardly diverging perforate centrifuge drum rotatable within said housing about a generally vertical axis; and inlet means for'feeding said mixture onto the interior of said drum, said inlet means including a tubular body co axially mounted with respect to said drum and rotatable therewith at an upper end thereof, said body being formed with a passage for said mixture terminating at an outlet within the interior of said drum, a downwardly diverging frustoconical bafl'le body axially spaced from said tubular body and formed with a wall extending transversely to the axis thereof forwardly of said outlet in the direction of flow of said mixture, and at least one rod-shaped elongated deflecting member extending downwardly from said tubular body to said baflie body in a plurality of diverging axially spaced spiral segments with adjacent spiral segments defining therebetween passageways transverse to said axis, the space bounded by said deflecting mem- 5 her between said tubular body and said baflle body being unobstructed, the bodies and said deflecting member being jointly rotatable with said drum for limiting upward movement of the mixture discharged at said outlet.

3. The combination defined in claim 1 wherein said baflle body and saidtubular body are formed integrally with one another and with said deflecting member 4. The combination defined in claim 1 wherein said drum is provided at an upper end thereof with a central References Cited by the Examiner UNITED STATES PATENTS 1,235,193 7/1917 Elmore 2l0-374 FOREIGN PATENTS 517,279 2/ 1953 Belgium. 1,021,718 12/1952 France.

OTHER REFERENCES hub having an upwardly tapering fr ustoconical bore, said 10 German printed application No. 1,074,503, January tubular body being of upwardly convergent frustoconical configuration and being fitted into said bore, said baflie body being of downwardly divergent frustoconical configuration.

REUBEN FRIEDMAN, Primary Examiner.

1. DE CESARE, Assistant Examiner. 

1. IN A CENTRIFUGE FOR THE SEPARATION OF SOLIDS FROM LIQUID IN A FLUENT HETEROGENEOUS MIXTURE THEREOF, IN COMBINATION, HOUSING MEANS FORMING AN ENCLOSURE; A DOWNWARDLY DIVERGING PERFORATE CENTRIFUGE DRUM ROTATABLE WITHIN SAID HOUSING ABOUT A GENERALLY VERTICAL AXIS; AND INLET MEANS FOR FEEDING SAID MIXTURE ONTO THE INTERIOR OF SAID DRUM, SAID INLET MEANS INCLUDING A TUBULAR BODY COAXIALLY MOUNTED WITH RESPECT TO SAID DRUM AND ROTATABLE THEREWITH AT AN UPPER END THEREOF, SAID BODY BEING FORMED WITH A PASSAGE FOR SAID MIXTURE TERMINATING AT AN OUTLET WITHIN THE INTERIOR OF SAID DRUM, A BAFFLE BODY AXIALLY SPACED FROM SAID TUBULAR BODY AND FORMED WITH A WALL EXTENDING TRANSVERSELY TO THE AXIS THEREOF FORWARDLY OF SAID OUTLET IN THE DIRECTION OF FLOW OF SAID MIXTURE, AND AT LEAST ONE ROD SHAPED ELONGATED DEFLECTING MEMBER EXTENDING DOWNWARDLY FROM SAID TUBULAR BODY TO SAID BAFFLE BODY IN AT LEAST ONE AXIALLY DIVERGING SPIRAL SEGMENT WITH ADJACENT SPIRAL PASSAGEWAYS TRANSVERSE TO SAID AXIS, THE SPACE BOUNDED BY SAID DEFLECTING MEMBER BETWEEN SAID TUBULAR BODY AND SAID BAFFLE BODY BEING UNOBSTRUCTED, THE BODIES AND SAID DEFLECTING MEMBER BEING JOINTLY ROTATABLE WITH SAID DRUM FOR LIMITING UPWARD MOVEMENT OF THE MIXTURE DISCHARGED AT SAID OUTLET. 